GEOLOGY OF THE BRISTOL COALFIELD. 2S5 



the Hnniphriesianiis zone ceases, but it is from them tliat the well- 

 known Dundry fossils are obtained. These are followed by about 

 twenty-three feet of limestone containing Ammonites {Cosmoceras) 

 Parkinsoni. 



On passing on to the back of the church we come to the quarries, 

 from which a line and coarse building stone is obtained, which is 

 in great request in Bristol and the vicinity. The coarse portion is 

 full of the casts of Trigoniae, and the debris of other shells with 

 what was originally sea sand. In many places the limestone is 

 pierced by the holes of Fithcdomi. The masons of the neighbour- 

 hood know well that when the Dundry freestone is used for 

 building, it must always be placed as it lay in the quarry, or during 

 a frost it is easily destroyed on exposure. This property is 

 universally recognised and borne in mind by all the local builders, 

 who give the name of ''top stone," because the stone in the 

 quarries forms the summit of the hill. The freestone beds may 

 easily be studied behind the Inn, near the church, as they lie 

 conformably on the top of the Humphriesianus series which, like 

 the Midford sands, are more easily seen on the southern side of the 

 summit, where they may be easily distinguished by an easily 

 weathered white, marly cement. The wall at the side of the road, 

 east of the church, will readily afford very perfect and well- 

 preserved specimens of all the typical Dundry corals. 



Wells sunk at the summit of the hill and which reach the Lias, 

 afford a copious s apply of delicious water. 



The Dimdry freestone is in colour and texture very similar to 

 that of Box and Bath, and Is so soft, when freshly quarried, that it 

 may be easily cut with a saw, but soon after, on exposure to the 

 atmosphere, attains a considerable degree of hardness. It Is very 

 porous and absorbent. Each cubic foot, in ordinary weather, will 

 take up about two gallons of water, but in rainy seasons much 

 more, which is of course a disadvantage when exposed afterwards 

 to a severe frost. Each cubic foot weighs 120 lbs, and each cubic 

 |nch will sustain a crushing power of more than 2,000 lbs. An 



